Determination of the biochemical and structural modifications in the cytoplasm of bovine oocytes during in vitro maturation by Raman microscopy

JIMÉNEZ, LUIS EMANUEL; ROLDÁN OLARTE, MARIELA; ALVAREZ, ROSA M.S

Congreso; XLVIII Reunión Anual Sociedad Argentina de Biofísica.; 2019

Sociedad Argentina de Biofísica

Determination of the biochemical and structural modifications in the cytoplasm of bovine oocytes during in vitro maturation by Raman microscopyJimenez, Luis Emanuel; Roldan-Olarte, Mariela; Álvarez, Rosa Maria.In recent years, studies to solve problems associated with assisted reproduction in bovines have become very important. The quality of oocytes is a determinant factor in the efficiency of in vitro reproduction process, therefore, being be able to identify competent oocytes for fecundation would be very important. During maturation, the complete oocyte undergoes biochemical and morphological changes, which can be separated in 2 different events, the nuclear and cytoplasmic maturation, synchronized with each other. The first, consists of chromosomal separation during the resumption of the first meiotic division, while the other event takes place with the reorganization of organelles and accumulation of mRNA, proteins, and lipids. The aim of this work is to study by Raman microscopy the cytoplasmic biochemical changes in bovine oocytes throughout in vitro maturation process. Immatures oocytes (IMM) and others that were 6, 18, and 22 hours (6H-MIV, 18H-MIV and 22H-MIV) under in vitro maturation conditions were studied. For a more precise analysis of the changes in the cytoplasm during in vitro maturation, the oocyte?s zona pellucida was removed using an enzymatic method. The spectra of the 6H-MIV group showed the intensities of the sugar bands decreased while the intensities of the lipids signals increased considerably, with respect to IMM spectrum. This suggests that sugar is used as energy source to increment the number of lipids drops, whose main component are triglycerides. The 18H-MIV spectra showed no spectral differences regarding the lipid and protein content when compared to the 6H-MIV group. The intensities of the characteristic protein bands appeared increased in the 22H-MIV spectra with respect to the other 3 groups. Indicating that the accumulation of proteins takes place toward the end of the maturation process. These results show that Raman spectroscopy can be used as a powerful analytical tool to analyze oocyte quality.